104 SMITHSONIAN INSTITUTION 



In the meantime Jaekel * had essayed a classification upon phylogenetic 

 grounds, which he applied in his subsequent important monograph upon the 

 Stammesgeschichte der Pelmatozoen, 1899. He, likewise, criticised the plan 

 of Wachsmuth and Springer because, in his opinion, they had dealt with the 

 morphological conditions as they found them too much from an anatomical 

 standpoint, and had not sufficiently taken into account the import of the modi- 

 fications due to descent. 



We have, therefore, two new and almost simultaneous phylogenetic classi- 

 fications, by two of the most eminent living authorities, both predicated in part 

 upon the insufficiencies of Wachsmuth and Springer's system, and each be- 

 lieved by its author to be an approximately correct reading of the race history 

 of the crinoids, according to the principles of modern Biology. But instead of 

 a concurrent result of the application of those principles, it appears that the 

 two classifications are about as fundamentally and diametrically opposed as 

 any two things could be. 



Bather, as already stated, finds in the presence or absence of infrabasals 

 ground for a primary division of the Crinoidea into two sub-classes, inde- 

 pendently developed from unknown ancestors, viz., Monocyclica and Dicyclica, 

 of which the Camerata and Inadunata are only subordinate divisions found in 

 each of the primary groups; and he splits the Camerata into two groups be- 

 cause he thinks the Platycrinidae and their allies depart too widely from the 

 typical form. 



Jaekel, on the other hand, does not recognize in the dicyclic or monocyclic 

 base a ground for large divisions at all. But he considers the Camerata a divi- 

 sion of even higher rank than its authors supposed, and accordingly erects it 

 into a sub-class under the name Cladocrinoidea, which he separates from all 

 other crinoids because he believes its representatives descended independently 

 from some of the many-plated cystids ; and the Platycrinoids he firmly retains 

 within this group. The remainder of the crinoids he groups in a sub-class of 

 equal rank with the Camerata, under the name Pentacrinoidea, within which 

 he places the Fistulata (W. and Spr.); Larvata (Larvifromia W. and Spr.); 

 Costata; Articulosa (Articulata, W. and Spr.) ; and Articulata (W. and Spr.; 

 Miiller). Monocyclic and dicyclic forms occur indiscriminately throughout 

 each of his basic groups. 



It is not my purpose at this time to undertake a discussion of the merits 

 of these two conflicting plans. The evidence upon which a final summing up 

 can be made is not yet in hand. It is my expectation, if time suffices, to follow 

 the present work with a similar treatment of the remaining group of Paleozoic 

 and partly Mesozoic crinoids, the Inadunata, in the hope that the necessary 



Sitzungs-Bericht Ges. Naturf., Berlin, Apr., 1894, P- 101. 



